Slush pump



July 22, 1941. W L ON 2.249.802

SLUSH PUMP Filed March 20, 1939 2 Sheets-Sheet l July 22, 1941- J. H. WiLSON SLUSH PUMP Filed March '20, 1939 2 Sheets-Sheet 2 grwem coc Patented July 22, 1941 UNITE o5 STATES PATENT 1 SLUSH-PUMP John Hart Wilson,'Wi'cliit'a; Falls; Tex. V Application March20, 1939;,S i 1 V V 7.01'aiins. (Cl. 74

This invention relates to power driven; pumps,- and more particularly to pumps of the type com-' monly used in connection with well' drilling operations, and known as slush pumps or mud pumps. Such pumps are commonly of the duplex double-acting type, andthe present invention, accordingly, will be described in COD-119C? tion with that type of pump. However, it will be understood that the features and advantagesof the present invention are not wholly limited to duplex pumps, or to double-actingpumps; although such features and advantages are particularly important in connection with heavy duty pumps for handling large volumes of fluids at relatively high pressures.

It is a general object of the'present invention to provide a slush pump of superior construction from the standpoint of ruggedness, durability, efficiency and economy, and more particularly to provide a pump having great mechanical strength while at the same time being of economical construction'in that the entire unit contains much less metal, by actual weight, and is of considerably smaller overall width thanpreviously known pumps of like capacity.

A principal feature of the present invention resides in the provision of a crank-shaft of novel design, which permits of an advantageous disposition of the main bearings and of the connecting rod bearings, as well as permitting the use of anti-friction bearings in both instances, which is not possible with other types of crank-shafts now commonly used in such pumps. Another object is the provision of novel and advantageous drive means connectingthe crank-shaft and the jack-shaft or power shaft of the pump, which drive means is particularly advantageous in connection with the novel crank-shaft employed.

A general object of the invention is to overcome certain disadvantages inherent in the construction of the slush pumps heretofore known. Such pumps consist g-enerally'of a pairof doubio-acting pump cylinders having the necessary valves and provided with pistons, a crank-shaft, connecting rods for driving the pistons from the crank-shaft, and means for driving the crankshaft. One important respect in which the pumps heretofore known have varied in construction lies in the design of the crank-shaft, the position and type of the main bearings, and the position and type of the connecting rod bearlngs.

Three principal arrangements have been employed in the past. In the first such arrangement, the-crank-sliaft has'been mounted in main bearings adjacent: itscenter i. e., on either side of the central gear wheel through which it is driven. and provided with overhung cranks secured to: the -respective;en'ds of: the crank shaft. This: arrangement permit-s of the use-of V anti friction main bearings aswell as anti-friction connecting rod'bear-ings, butisdisadvantageous in that the main bearings are very highly stressedbyreason. of the application of the connecting rodload at pointsoutside of the main bearing, necessitating theme of largebearings and involving a costlyconstructionq Also,

the placing ofthe main bearings inside of the cranks requires strengthening of the framework at these points, involving the use of heavybeams which add tothe weight and cost of the pump, as compared-Withone in which the main-bearings are supported in their logicalpositiomnamely, in theside frames of the casing which are normally the strongest parts of the frame-structure. In addition, the useof very large and heavy main bearings necessitates the use of 'split bearings which is disadvantageous in tha-tthe bearings must be bolted together; and the mechanism is thus subject to injury if' a bolt breaks, such bolts beingunder a very heavy load;

In'a second type'of construct-ion the' straigh-t crank-shaft is journalled', at its ends, in the side frames of the pumpand the connecting rods are supported on plain eccentricssecured on the crank-shaft or made integral with the central gear wheel; In this construction "the main load is transmitted to tiie'sideframes; in a proper manner, but the construction does not permit of the use of anti-friction connecting rod bearings and the eccentrics and connecting rod journals are thus subject to excessive wear and relatively high friction losses.

The thirdtype of arrangement employs a conventional crank-shaft journalled in the side frames, the connecting rods being supported on plain bearings se'cured'on the crank'throws, much as in the usual steam engine construction. This arrangement, like the second type described, is disadvantageous in notjpermitti'ng usero'f antifriction connecting rod bearings.

In the construction'according tothe present invention, the crank-shaft is'journalled in the side frames, in antifriction bearings, and due to the novel'design 'of' crankeshaftcmployed, these side frames may be placed closer together than would otherwise be the case;thus reducing the width of the unit and, greatly reducin friction connecting rod bearings may be used, the advantages thereof being obvious.

Other and further objects, features and advantages of the present invention will be apparent to one skilled in the art from the following description taken in connection with the accompanying drawings, in which:

Figure 1 is a longitudinal vertical section of a pump unit in accordance with the present invention;

Figure 2 is a transverse vertical section on line 22 of Figure 1;

Figure 3 is a horizontal section of the mechanism shown on the right in Figure 1, certain parts being shown in plan, for convenience; and

Figures 4 and 5 are an end elevation and a plan, respectively, of one of the removable end sections of the novel crank-shaft of the present invention.

In order to facilitate an understanding of the invention, reference is made .to the embodiment thereof shown in the accompanying drawings and detailed. descriptive language is employed. It will nevertheless be understood that no limitation of the invention is thereby intended and that various changes and alterations are contemplated suchas would ordinarily occur to one skilled in the art to which the invention relates.

Referring to the drawings,,it will be seen that the pump of the present invention comprises, generally, the usual cylinders I0, which are provided with suitable inlet and discharge passages and valves, the pistons II, piston rods I2, slides I3, guides I4, and connecting rods I5, I5, articulated with the slides I3. The connecting rods I5, I5 are journalled on anti-friction roller bearings I6, carried on a crank-shaft I! (Figure 3). The latter comprises a central section or portion I8, constituting a pair of crank-pins and a. diagonal or oflset portion connecting said crank-pins, and two similar L-shaped end sections I9, I9. The L-shaped sections are illustrated in Figures land 5, and are adapted tobe splined and bolted upon the respective ends of the centralcrank-shaft section I8, outside of the connecting rod bearings I6. The webportions of the L-shaped sections I9, I9 which extend at right angles tothe central section I8 are mutually angularly displaced by 90, the outwardly turned journal portions of said L-shaped sections being in alignment and being journalled in suitable anti-friction bearings carried in the side frames or casing walls12I. By virtue of the shape of the crank-shaft it will be seen that the central section I8 moves in an orbit about the axis of the bearingsZII, thus actuating the connecting rods I5, I5 in proper phase relation. The end sections I9, I9 being removable, the anti-friction connecting rod bearings I6 may be inserted in place without difficulty.

, The anti-friction bearings 20 are carried in bearing cages 20', which are in turn bolted or otherwise suitably secured in the casing Walls 2|. The cages 2B are of relatively large diameter, in order to facilitate assembling and disassembling of the pump. Thus, in assembling the pump, after .the central crank-shaft section 18, with the connecting rodsijournalled" thereon, has beenput in.place, through the large opening in the rear of the casing, closed by the cover plate 2| (Figure: 1-), the end sections l9 and I9 may be inserted through the main. bearing apertures and slipped onto the respective splined ends of the central section-I8, to which they are rigidily secured by bolts." The bearing cages 20'; carrying the bearings 20, are then put in place and bolted to the casing walls.

Since the crank-shaft of the present invention is subject to some deflection, it is preferred to employ main bearings and connecting rod bearings of the self-aligning type, as illustrated, which are capable of compensating for any possible deflection of the crank-shaft without damage to the bearings.

Since the crank-shaft above described will, in heavy service, be subject to a certain amount of deflection, it is preferred to use a chain drive in lieu of the usual direct gear drive, although the present organization is by no means limited to use with chain drives alone. In the present embodiment, a sprocket wheel 22 (Figures 1 and 3) is mounted eccentrically on the central section l8 of the crank-shaft at the point where the offset occurs in the latter. The Wheel 22 has its center in line with the bearings 20, but since no part of the central section I8 of the crank-shaft lies on this axis, it isnecessary to mount the wheel 22 eccentrically with respect to the latter. The section I8 is thereforeprovided with an integral flange I8, and the Wheel 22 is formed with an eccentric hub 22' which is adapted to be bolted to the flange I8. The sprocket wheel 22 is driven through a chain 23 from a sprocket pinion 24 carried on the jackshaft 25 (Figure 2), which latter is journalled in anti-friction bearings 28', 2'1 and 28. The outer end of the jack-shaft 25 carries means for receiving power from an external source, illus trated in the present embodiment as a multiple V-belt sheave 29. Preferably, an automatic chain tightener 30 is employedin connection with the chain 23, as seen in Figure 1.

By reason of the mode in which the sprocket wheel 22 is mounted on the contral section I8 of the crank-shaft, that is, at the point where the offset occurs rather than on a straight portion provided between two offsets, as in the case of a conventional crank-shaft, it is apparent that the overall length of the crank-shaft may be considerably reduced, thus reducing the overall width of the entire pump unit, and effecting a considerable economy in metal. It will also be apparent that the present arrangement of the crankshaft, connecting rods and bearings results in a strong and rugged construction which, at the same time, is adapted to operate with a minimum of'friction, thus reducing friction losses and conducing to the long life of the moving parts. Furthermore, it will be readily understood that by reason of the present construction the connecting rod load is transmitted to the side frames of the unit, which are normally the strongest parts of the frame, and it is unnecsary to provide special reinforcing members inwardly of the side frames, as in the case when the crank-shaft is supported on bearings lying inwardly of its ends.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is: V

1. In a power driven pump of the duplex double-acting heavy duty type, a crankshaft comprising two aligned axially extending end portions, opposed portions extending transversely. to said end portions and arranged at an angle of substantially to each other, and a central portion connecting the ends of said opposed portions, said central portion being disposed eccentrically to the axis of the crankshaft and having a lateral offset, and a power-receiving member eccentrically secured on said central portion at the point where said offset occurs.

2. In a power driven pump of the duplex double-acting heavy duty type, a crankshaft comprising a central section disposed eccentrically to the axis of the crankshaft and having a lateral offset and two L-shaped end sections removably secured on the respective ends of said central section, each said L-shaped section comprising an axially extending journal portion and a transverse web portion, said web portions being disposed at an angle of substantially 90 to each other, and a power receiving member eccentrically secured on said central section at the point where said offset occurs.

3. In a power driven pump of the duplex double-acting heavy duty type, a frame including a pair of parallel longitudinal outer walls, a crankshaft journalled at its ends in anti-friction bearings carried by said respective walls, said crankshaft comprising two aligned axially extending end portions, opposed portions extending transversely to said end portions and arranged at an angle of substantially 90 to each other, and a central portion connecting the ends of said opposed portions, said central portion being disposed eccentrically to the axis of the crankshaft and having a lateral offset, and a power-receiving member eccentrically secured on said central portion at the point where said offset occurs.

4. In a power driven pump of the duplex double-acting heavy duty type, a crankshaft comprising a central section disposed eccentrically to the axis of the crankshaft and having a lateral offset and two L-shaped end sections removably secured on the respective ends of said central section, each said L-shaped section comprising an axially extending journal portion and a transverse web portion, said web portions being disposed at an angle of substantially 90 to each other, anti-friction hearings on said central section on either side of said offset, connecting rods journalled on said anti-friction bearings, and a power receiving member eccentrically secured on said central section at the point where said offset occurs.

5. In a power driven pump of the duplex double-acting heavy duty type, a frame including a pair of parallel longitudinal outer walls, a crankshaft journalled at its ends in anti-friction bearings carried by said respective walls, a jack-shaft journalled in said frame, and means including a power receiving member on said crankshaft for affording a driving connection between said jackshaft and crankshaft, said crankshaft comprising two aligned axially extending end portions, opposed portions extending transversely to said end portions and arranged at an angle of substantially to each other, and a central portion connecting the ends of said opposed portions, said central portion being disposed eccentrically to the axis of the crankshaft and having a lateral oifset, and said power receiving member being eccentrically secured on said central portion at the point where said offset occurs.

6. In a power driven pump of the duplex douole-acting heavy duty type, a frame including a a pair of parallel longitudinal outer walls, a crankshaft journalled at its ends in anti-friction bearings carried by said respective walls, said crankshaft comprising a central section disposed eccentric-ally to the axis of the crankshaft and having a lateral offset and two L-shaped end sections removably secured on the respective ends of said central section, each said L-shaped section comprising an axially extending journa1 portion and a transverse web portion, said web portions being disposed at an angle of substantially 90 to each other, anti-friction hearings on said central section on either side of said offset, connecting rods journalled on said anti-friction bearings, and a power receiving member eccentrically secured on said central section at the point where said offset occurs.

7. In a power driven pump of the duplex .doub le-acting heavy duty type, a crankshaft comprising two aligned axially extending end portions, opposed portions extending transversely to said end portions and arranged at an angle of substantially 90 to each other, and a central portion connecting the ends of said opposed portions, said central portion being disposed eccentrically to the axis of said crankshaft and comprising two crank-pin portions extending parallel to the axis of the crankshaft and a diagonal portion connecting said crank-pin portions, and a power receiving member eccentrically secured on said diagonal portion and having its axis coincident with the axis of said crankshaft.

JOHN HART WILSON. 

